1. Field of the Invention
The present invention relates to an integrated circuit having a first layer, made of active semiconductor material and extending along a first side of a buried layer, and trench structures, which cut through the layer made of active semiconductor material and have dielectric wall regions, whereby the dielectric wall regions electrically isolate subregions of the layer, made of active semiconductor material, from one another in the lateral direction, and whereby the trench structures, furthermore, have first inner regions, which are filled with electrically conductive material and contact the buried layer in an electrically conductive manner. The invention relates furthermore to a method for manufacturing such an integrated circuit.
2. Description of the Background Art
An integrated circuit of is known from U.S. Publication No. 2002/0008299 A1. This publication shows trench structures with dielectric wall regions and electrically conductive fillings. Active regions of a semiconductor layer disposed above a buried layer are electrically isolated from one another in a lateral direction by dielectric wall regions. Buried regions are contacted electrically from a surface of the integrated circuit with the electrically conductive fillings. For this purpose, a downwardly open, conductively filled trench ends in each case in a buried region.
It is not possible in this way, however, to achieve a lateral dielectric separation of subregions of a buried layer, which lie under different, for example, under neighboring active regions. In addition, only one level of a trench structure can be electrically contacted by the structures disclosed in U.S. Pat. Application No. 2002/0008299 A1. This type of separation is desirable, however, to control the different active regions with individual electrical properties of the underlying buried regions.
U.S. Pat. No. 6,316,336 discloses a trench structure through which a buried layer is formed and contacted. Disadvantageous hereto is that for forming an extended buried layer, a plurality of tightly bordering trench structures are required and a high temperature is needed for the lateral distribution of a dopant.
From US Publication No. 2003/00017710 a trench structure for forming a shallow trench isolation (STI) is known, through which a repeated application of a silicide etching and a spacer etching an incline in the trench profile is formed. A problem of such structures is that a width of the trench structure is larger than a depth of the trench structure, and that such structures are used for isolation between individual components.